I did not want to offend anyone, but there are certain objective criteria which allow comparing US and European institutions (publications, placement etc.). Although, it is undoubtedly hard, because the systems are indeed different. I personally believe that German universities are of a high standard, but there are certainly no internationally recognized top institutions. There is no Harvard here, sorry. Science (even social) is international and thus the fact of not publishing in English is an indicator of weakness, not unfairness of world rankings towards Germany.
But it is not all that depressing. For instance, Mannheim is ranked higher (#49) than Brown (#50) in the recent QS ranking on politics. FU is also doing a great job in terms of internationalization, but the truth is that it can be hardly compared to the top 50 in the US (which are btw great institutions such as John Hopkins, UC Irvine, Boulder, Vanderbilt etc.)
So, would you rather study in FU or in Brown?